My PowerMac G4 Lucky Dip (Twins!)

[LightBulbFun]

Very nice write up glad everything worked out in the end

very nice Job on the ATA connector mod im pretty sure your the first person to keep that intact, I wonder if the same mods would work for a G4 cube as I think the same issue plagues the G4 cube where if you try and fit a "Left handed" G4 CPU card it hits an ATA connector but I have not personally worked on a cube so someone else can chime in on that.

also nice Job on the Coil mod its good to know that it fowls the heatsink as I have not ever seen it mentioned anywhere before I dont think...

im not too surprised the heatsink gets hot the 7450 is a much hotter running chip. the 733Mhz 7450 in your card at full tilt at 733Mhz has a TDP of 29W vs the 7410 @ 533Mhz with a TDP of 15W thats almost a doubling of the TDP

its pretty neat to see the direct comparison of the 7410 vs 7450 it pretty much confirms that clock for clock a 7410 is faster... (yay for the 4 stage pipeline )

in regards to the PLL resistors im not surprised they are the same since the those resistors control pins on the CPU which are the same between the DA and QS since they both use the same CPU The resistors just pull a set of pins on the CPU low or high. on a PPC Machine once you figure out which Resistor is which for which PLL then its easy to figure out how to set them by referencing the corresponding data-sheet for whatever PPC CPU the machine has

if you want a more extensive PLL chart then the overclocking guides normally give check out the NXP/Freescale/Motorola data-sheet for whatever CPU your trying to overclock its worth noting that in the Data-sheet charts 0 means set a resistor/jumper and 1 means no jumper/resistor usually

for example for your 733 card https://www.nxp.com/docs/en/data-sheet/MPC7450EC.pdf PLL chart starts on Page 36 and here is the 7410 data-sheet https://www.nxp.com/docs/en/data-sheet/MPC7410EC.pdf PLL chart starts on page 34

its also worth noting your 733Mhz XPC7450RX733PD has its own Data-sheet separate from the main 7450 one. https://www.nxp.com/docs/en/data-sheet/MPC7450PXPNS.pdf?fsrch=1&sr=7&pageNum=1 the same is true for the XPC7410RX533PD https://www.nxp.com/docs/en/data-sheet/MPC7410PDPNS.pdf?fsrch=1&sr=1&pageNum=1

as for Gauge Pro, Yeah Gauge Pro will only recognise up to a 7410 or so, for anything newer Sonnet Metronome or PowerLogixs CPU Director is your best bet and yeah the 7450 does not have any sort of thermal diode or TAU (Thermal assist unit)... so your just gonna have to check your temps by seeing how well that Egg cooks

(speaking of cooking an egg you should try Volt mod the 7410 and see if you can hit 650Mhz )

 

[AphoticD]

Thanks Dez, it's not the prettiest, but the ODD mod seemed to work out okay.

I am really impressed with the 7410 CPU then, it performs great for the heat it puts out. I should try the 650Mhz step next, it will probably be faster than the 7450 @ 700Mhz.

I wonder what kind of tricks Apple had to do to keep the 7450 running cool in those early TiBooks. I didn't realize it would run so hot.

Another observation is that Mac OS 8.6 doesn't seem to want to boot now... Maybe it doesn't know what to do with the 7450? I'll have to move the partition across to the machine with the 7410 now.

EDIT: Here is Metronome's report on the new CPU:

 

[LightBulbFun]

Thanks Dez, it's not the prettiest, but the ODD mod seemed to work out okay.

I am really impressed with the 7410 CPU then, it performs great for the heat it puts out. I should try the 650Mhz step next, it will probably be faster than the 7450 @ 700Mhz.

I wonder what kind of tricks Apple had to do to keep the 7450 running cool in those early TiBooks. I didn't realize it would run so hot.

Another observation is that Mac OS 8.6 doesn't seem to want to boot now... Maybe it doesn't know what to do with the 7450? I'll have to move the partition across to the machine with the 7410 now.

your mods are very pretty compared to what I would of come up with!

indeed the 7410 is quite a nice chip I think in some altivec scenarios the 7450 etc can beat out a 7410 but the 7 stage pipe line of the 7450 does not help it clock for clock, it does help get the Clock speed up tho. the 7410 vs 7450 is much like the Pentium 3 vs the first Pentium 4 chips.

http://www.xlr8yourmac.com/G4ZONE/sawtooth/SawtoothCPUdesign.html if you scroll to the bottom here you can find out how to bump up the Core voltage on the 7410 card 2.1V is the max core voltage before things start getting hairy for the 7410 according to Motorola. (all the 7400/7410 CPU cards from apple seem to share the same layout)

in regards to the 7450s in the TiBooks, apple only used those in the 550/667Mhz PowerBook3,3. not very fast compared to the 733 7450 you have there where also a few diffrent grades of 7450, im guessing apple would of used the coolest running/lower core voltage ones, I have not seen a picture of the GigE VGA TiBooks CPU so I dont know which PDF to pull up to check out the TDP. (the Schematic does not mention it sadly)

heat wise it prolly does not help that you have the earliest CPU card model to use 7450s (notice its only Rev 2.0, most 7450s are Rev 2.1)

and Yeah Mac OS 8.6 wont boot unless you jump into OF/write an nvramrc script to Fake the PVR value to that of a 7400, the Mac OS ROM wont boot on unknown PVR values (aka wont boot on CPUs unknown to it) I was surprised 8.6 Boots on the 7410 even, faking the PVR is one of the things you have to do to boot Mac OS 8.6 on an MDD or Mac OS 9.2.2 on a 7447-7448 Mac its why so many 7447-7448 CPU upgrades mask the PVR value to something else like a 7455 so Mac OS 9 will boot.

to do change the PVR, and boot Mac OS 8.6, set Mac OS 8.6 as the start up disk then boot into OF and type the following:

dev /cpus/PowerPC,G4<enter>

000c0207 encode-int " cpu-version" property<enter> (this sets the PVR to that of a Rev 2.7 7400)

boot<enter>

it should then Boot Mac OS 8.6, keep in mind this is not saved to any sort of NVRAM so will not survive across reboots. I can look into making an nvram script for you if you want something more permanent

 

[pc297]

I was surprised to see my 500Mhz 7410 be stable at 600 (maybe some day ill try my luck at 650)

Which CPU is this? Did you have to increase Vcore (tricky with those small resistors I hear)? On my B&W G3 I have 600 MHz too with my OWC Mercury G4 ZIF 500-550 MHz (7410 "nitro" as well) but only in the winter/late fall/early spring due to the infamous errata bug 🤣 Thinking of increasing Vcore on it following those instructions rather than relying on the ambient temperature in my basement going below 22C:

G4/400 Yikes w/Voltage Tweak runs 500MHz